Estimated depletion, of both oil and coal, seems to match. Looks like ~54 years, or so, is all you get, from both.
— http://en.wikipedia.org/wiki/Proven_oil_reserves#Estimated_reserves_by_country
If demand softens, because alternatives become competitive, then this time frame extends.
But if extraction becomes cheaper, then the price drops, demand strengthens, and the time frame contracts.
As fusion is deployed, it will meet energy demand increases first, so i don’t see the above numbers changing a lot, near term.
